Synthesis of Allylthiopyridazine Derivatives and Inhibition of Aflatoxin B<Subscript>1</Subscript>-Induced Hepatotoxicity in Rats

Five kinds of allylthiopyridazine derivatives were synthesized and their chemoprotective activities examined in rats exposed to aflatoxin B1-toxicant. Rats were pretreated with five allylthiopyridazine derivatives at daily oral doses of 50 mg/kg for 10 consecutive days, and during this period with one or three repeated doses of the potent hepatotoxin, aflatoxin B1. The hepatoprotective effects of the allylthiopyridazine derivatives against aflatoxin B1 (1 mg/kg, three times at intervals of 3 days, i.p., or at 3 mg/kg, once at final days, i.p.) administration were showed the significantly normal as compared with control in body and liver weights. Aspartate aminotransferase and alanine aminotransferase levels were markedly elevated after aflatoxin B1 administration, and pretreatment with allylthiopyridazine derivatives, before aflatoxin B1 administration, resulted in decreased levels of these enzymes. In addition, the allylthiopyridazine derivatives, K6 (3-methoxy-), K8 (3-chloro-), K16 (3-ethoxy-) and K17 (3-n-propoxy), induced elevated hepatic GSH levels. Four kinds of allylthiopyridazine derivatives investigated were effective against aflatoxin B1-induced hepatotoxicity.     

Chemopreventive effects of 2-(Allylthio)pyrazine

A series of organosulfur compounds were synthesized with the aim of developing chemopreventive compounds active against hepatotoxicity and chemical carcinogenesis. 2-(Allylthio) pyrazine (2-AP) was effective in inhibiting cytochrome P450 2E1-mediated catalytic activities and protein expression, and in inducing microsomal expoxide hydrolase and major glutathione S-transferases. 2-AP reduced the hepatotoxicity caused by toxicants and elevated cellular GSH content. Development of skin tumors, pulmonary adenoma and aberrant crypt foci in colon by various chemical carcinogens was inhibited by 2-AP pretreatment. Anticarcinogenic effects of 2-AP at the stage of initiation of tumors were also observed in the aflatoxin B₁ (AFB₁)-induced three-step medium-term hepatocarcinogenesis model. Reduction of AFB₁-DNA adduct by 2-AP appeared to result from the decreased formation of AFB₁-8,9-epoxide via suppression of cytochrome P450, while induction of GST by 2-AP increases the excretion of glutathione-conjugated AFB₁. 2-AP was a radioprotective agent effective against the lethal dose of total body irradiation and reduced radiation-induced injury in association with the elevation of detoxifying gene expression. 2-AP produces reactive oxygen speciesin vivo, which is not mediated with the thiol-dependent production of oxidants and that NF-κB activation is not involved in the induction of the detoxifying enzymes. The mechanism of chemoprotection by 2-AP may involve inhibition of the P450-mediated metabolic activation of chemical carcinogens and enhancement of electrophilic detoxification through induction of phase II detoxification enzymes which would facilitate the clearance of activated metabolites through conjugation reaction.     

Hepatoprotective and toxicological assessment of an ethnomedicinal plant Euphorbia fusiformis Buch.-Ham.ex D.Don

Aim of the study

The tubers of Euphorbia fusiformis Buch.-Ham.ex D.Don (Euphorbiaceae) are traditionally used in India by the Malayali tribes of Chitteri hills, Eastern Ghats, Tamil Nadu to treat liver disorders. The objective of the present study was to assess the hepatoprotective potential and biosafety of Euphorbia fusiformis tuber upon administration thereby justifying the traditional claims.

Materials and methods

The hepatoprotective potential of the ethanol extract of Euphorbia fusiformis tuber against rifampicin induced hepatic damage was investigated in Wistar albino rats. The acute and subchronic toxicity were assessed in mice and rats, respectively.

Results

The ethanol extract of tubers (250 mg/kg p.o.) showed remarkable hepatoprotective effect against rifampicin induced hepatic damage in Wistar albino rats. The degree of protection was measured using the biochemical parameters serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT), gamma glutamyl transpeptidase (GGTP), alkaline phosphatase (ALP), total bilirubin and total protein. Treatment with ethanolic extract prior to the administration of rifampicin significantly (P < 0.05 to P < 0.001) restored the elevated levels of the said parameters on a par with the control group. The single dose LD₅₀ was found to be 10,000 mg/kg bw when administered orally in mice. Subchronic toxicity studies in rats with oral doses of 125, 250 and 500 mg/kg exhibited no significant changes in body weight gain, general behavior, hematological and biochemical parameters. The histological profile of liver and kidney also indicated the non-toxic nature of this drug.

Conclusion

The ethanol extract of Euphorbia fusiformis tubers may have potential therapeutic value in the treatment of liver disorders and is safer to use even at higher doses when taken orally.     

The genus Scutellaria an ethnopharmacological and phytochemical review

Scutellaria (HUANG QIN) (Lamiaceae), which includes about 350 species commonly known as skullcaps, is widespread in Europe, the United States and East Asia. Some species are taken to clear away the heat-evil and expel superficial evils in traditional Chinese medicine (TCM). The present paper reviews the ethnopharmacology, the biological activities and the correlated chemical compounds of Scutellaria species. More than 295 compounds have been isolated, among them flavonoids and diterpenes. Studies show that Scutellaria and its active principles possess wide pharmacological actions, such as antitumor, anti-angiogenesis, hepatoprotective, antioxidant, anticonvulsant, antibacterial and antiviral activities. Currently, effective monomeric compounds or active parts have been screened for pharmacological activity from Scutellaria in vivo and in vitro. Increasing data supports application and exploitation for new drug development.     

Hepatoprotective and in vivo antioxidant effects of Byrsocarpus coccineus Schum. and Thonn. (Connaraceae)

Ethnopharmacological relevance

The leaf decoction of Byrsocarpus coccineus (Connaraceae) is drunk for the treatment of jaundice in West African traditional medicine.

Aim of the study

To investigate the hepatoprotective and in vivo antioxidant effects of Byrsocarpus coccineus in carbon tetrachloride (CCl₄)-induced hepatotoxicity in rats.

Materials and methods

Group allotment in this study included vehicle, CCl₄, Byrsocarpus coccineus 1000 mg/kg alone, Byrsocarpus coccineus 200, 400, and 1000 mg/kg + CCl₄ and Livolin^® 20 mg/kg + CCl₄, and treatment was carried out accordingly. On the 7th day, rats were sacrificed and blood was withdrawn by cardiac puncture. The levels and activities of serum biochemical parameters and antioxidant enzymes were then assayed using standard procedures.

Results

CCl₄ significantly (P < 0.05) increased the levels of ALT and AST and reduced total protein. In CCl₄ treated animals, Byrsocarpus coccineus (200, 400, and 1000 mg/kg) dose-dependently and significantly decreased ALT, AST and ALP levels with peak effect produced at the highest dose. Conversely, Byrsocarpus coccineus produced significant increases in albumin and total protein levels. The standard drug produced significant effects in respect of ALT (↓), albumin (↑), and total protein (↑). CCl₄ also produced significant (P < 0.05) reductions in the activity of catalase, SOD, peroxidase and GSH, and conversely increased MDA level. Byrsocarpus coccineus produced significant and dose-dependent reversal of CCl₄-diminished activity of the antioxidant enzymes and reduced CCl₄-elevated level of MDA. The standard drug also significantly increased CCl₄-diminished antioxidant enzymes activity and reduced CCl₄-elevated MDA level. In general, the effects of the standard drug were comparable and not significantly different from those of Byrsocarpus coccineus.

Conclusion

The results obtained in this study suggest that the aqueous leaf extract of Byrsocarpus coccineus possesses hepatoprotective and in vivo antioxidant effects. This finding justifies the use of this preparation in West African traditional medicine for the treatment of liver disease.     

Hepatoprotective effect of flavonol glycosides rich fraction from egyptianVicia calcarata desf. Against CCI4-induced liver damage in rats

The hepatoprotective activity of flavonol glycosides rich fraction (F-2), prepared from 70% alcohol extract of the aerial parts of V. calcarata Desf., was evaluated in a rat model with a liver injury induced by daily oral administration of CCl4 (100 mg/kg, b.w) for four weeks. Treatment of the animals with F-2 using a dose of (25 mg/kg, b.w) during the induction of hepatic damage by CCl4 significantly reduced the indices of liver injuries. The hepatoprotective effects of F-2 significantly reduced the elevated levels of the following serum enzymes: alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH). The antioxidant activity of F-2 markedly ameliorated the antioxidant parameters including glutathione (GSH) content, glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), plasma catalase (CAT) and packed erythrocytes glucose-6-phosphate dehydrogenase (G6PDH) to be comparable with normal control levels. In addition, it normalized liver malondialdehyde (MDA) levels and creatinine concentration. Chromatographic purification of F-2 resulted in the isolation of two flavonol glycosides that rarely occur in the plant kingdom, identified as quercetin-3, 5-di-O-beta-D-diglucoside (5) and kaempferol-3, 5-di-O-beta-D-diglucoside (4) in addition to the three known compounds identified as quercetin-3-O-alpha-L-rhamnosyl- (1-->6)-beta-D-glucoside [rutin, 3], quercetin-3-O-beta-D-glucoside [isoquercitrin, 2] and kaempferol-3-O-beta-D-glucoside [astragalin, 1]. These compounds were identified based on interpretation of their physical, chemical, and spectral data. Moreover, the spectrophotometric estimation of the flavonoids content revealed that the aerial parts of the plant contain an appreciable amount of flavonoids (0.89%) calculated as rutin. The data obtained from this study revealed that the flavonol glycosides of F-2 protect the rat liver from hepatic damage induced by CCl4 through inhibition of lipid peroxidation caused by CCl4 reactive free radicals.     

Phytochemical and pharmacological study of Ficus palmata growing in Saudi Arabia

Phytochemical study of the aerial parts of Ficus palmata utilizing liquid–liquid fractionation and different chromatographic techniques resulted in the isolation of a new isomer of psoralenoside namely, trans-psoralenoside (5) in addition to, one triterpene: germanicol acetate (1), two furanocoumarins: psoralene (2), bergapten (3), one aromatic acid vanillic acid (4) and the flavone glycoside rutin (6). Structures of the isolated compounds were established through physical, 1D- and 2D-NMR and MS data. The total extract and fractions of the plant were examined in vivo for its possible effects as hepatoprotective, nephroprotective, antiulcer and anticoagulant activities in comparison with standard drugs. Hepatoprotective activity was assessed via serum biochemical parameters including aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma glutamyl transpeptidase (GGT), alkaline phosphatase (ALP) and total bilirubin. Tissue parameters such as non-protein sulfhydryl groups (NP-SH), malonaldehyde (MDA) and total protein (TP) were also measured. In addition to tissue parameters, nephroprotective effect was evaluated by measuring the serum levels of sodium, potassium, creatinine and urea. Histopathological study for both liver and kidney cells was also conducted. Antiulcer activity was explored by observing stomach lesions after treatment with ethanol. Whole blood clotting time (CT) was taken as a measure for the anticoagulant activity of the extract. Antioxidant activity of the total extract and fractions of the plant was measured using 2,2-diphenyl-1-picrylhydrazyl (DPPH) method and ascorbic acid as standard.     

Analgesic,antipyretic, anti-inflammatory,hepatoprotective and nephritic effects of the aerial parts of Pulicaria arabica (Family: Compositae) on rats

ObjectiveTo explore the analgesic, antipyretic, anti-inflammatory, hepatic and nephritic effects of Pulicaria arabica (P. arabica) in several experimental models.MethodsFor analgesic effect hot plate and writhing method were used, while for antipyretic and anti-inflammatory rectal temperature and carrageenan induced hind paw edema were used respectively. CCl₄ intoxication method was used for hepatic and nephritic protective activity.ResultsThe results of the present studies revealed that P. arabica has potent analgesic, antipyretic and anti-inflammatory with the significant hepatic and nephritic protecting actions. The CCl₄ intoxication changed the normal malondialdehyde and nonprotein sulfhydryls levels in both liver and kidney. These changes were normalized with P. arabica indicating the antioxidant nature of this plant.ConclusionsThe results of present study indicated that P. arabica can be used in analgesic, antipyretic and anti-inflammatory conditions even in hepatic and nephritic conditions. More supportive studies are required before clinical recommendation.     

Hepatoprotective and antioxidant capacity of Melochia corchorifolia extracts

ObjectiveTo evaluate hepato protective and antioxidant capacity of Melochia corchorifolia (M. corchorifolia) aerial part extracts.MethodsAntioxidant activity was evaluated by using three free radicals (Superoxide, Hydroxyl and DPPH) and hepatoprotective activity was assessed against CCl₄ induced liver intoxication in rats.ResultsThe extracts produced concentration dependent percentage protection in decrease of serum enzymes and percentage inhibition on free radicals. Among all extracts methanol extract showed better activity with percentage protection of SGOT (78.98%), SGPT (79.65%), ALP (82.48%) and total bilirubin (80.0%) levels against CCl₄ liver intoxication and also methanolic extract showed better activity with IC₅₀ values on superoxide, hydroxyl and DPPH radicals were 127 μ g, 240 μ g and 179 μ g.ConclusionsFrom the results obtained during the study it could be concluded that M. corchorifolia aerial part extracts have antioxidant and hepatoprotective components. Further study is necessary for isolation and characterization of bioactive molecules which are responsible for hepatoprotective and antioxidant activity.     

Evaluation of hepatoprotective effect of methanolic extract of Clitoria ternatea (Linn.) flower against acetaminophen-induced liver damage

Objective

To evaluate the hepatoprotective and antioxidant activity of Clitoria ternatea (C. ternatea) flower extract against acetaminophen-induced liver toxicity.

Methods

The antioxidant property of C. ternatea flower extract was investigated by employing established in vitro antioxidant assay. The C. ternatea flower extract was studied in this work for its hepatoprotective effect against acetaminophen-induced liver toxicity in mice. Activity was measured by monitoring the levels of aspartate aminotransferase, alanine aminotransferase, billirubin and glutathione with histopathological analysis.

Results

The amount of total phenolics and flavonoids were estimated to be 105.40±2.47 mg/g gallic acid equivalent and 72.21±0.05 mg/g catechin equivalent respectively. The antioxidant activity of C. ternatea flower extract was 68.9% at a concentration of 1 mg/mL and was also concentration dependant, with an IC₅₀ value of 327.00 µg/mL. The results of acetaminophen-induced liver toxicity experiment showed that mice treated with the extract (200 mg/kg) showed a significant decrease in alanine aminotransferase, aspartate aminotransferase, and bilirubin levels, which were all elevated in the paracetamol group (P<0.05). Meanwhile, the level of glutathione was found to be restored in extract treated animals compared to the groups treated with acetaminophen alone (P<0.05). Therapy of extract also showed its protective effect on histopathological alterations and supported the biochemical finding.

Conclusion

The present work confirmed the hepatoprotective effect of C. ternatea flower against model hepatotoxicant acetaminophen.